1. Field of the Invention
The present invention relates to ion-exchange and filter water systems, and, more particularly, to an ion-exchange resin bed system.
2. Description of the Related Art
Ion-exchange water treatment systems may be of two general types, i.e., a timed system and a demand system. A timed system utilizes a timer to regenerate a resin bed within a treatment tank of the water treatment system after a particular period of time has elapsed. With a timed system, it is necessary to estimate, based upon the users application demand, water usage history, etc., when the treatment tank should be regenerated. If actual water usage exceeds the capacity of the unit during the time period, "untreated" water (i.e., water containing impurities such as iron, calcium and magnesium) could be output by the water treatment system. Accordingly, timed water treatment systems are typically regenerated well ahead of the point when the total amount of normal water use would occur to prevent the occurrence of such "untreated" water. Such systems have the disadvantage of discharging excess water and regenerant, e.g., salt, into a sewer system, with associated detrimental environmental impact.
A demand system of conventional design utilizes a flow meter (or turbine) at the output valve of the treatment tank to count the actual amount of water used since the last regeneration. The flow meter outputs signals to an electronic counter which initiates regeneration when the pre-set count (corresponding to a total amount of flow through the treatment tank outlet) equals a preset amount corresponding to an exchange capacity of the resin bed within the treatment tank. However, such systems are limited by the sensitivity of the flow meter. Such meters are not typically able to count all the flow therethrough in a small amount per unit of time, such as caused by drips from sinks, appliances, etc. Also, such meters are unable to register if an overlap or overdrive occurred at extremely high flow rates. Such small amounts of water which actually pass through the flow meter (or turbine) but which are not detected thereby actually amount to several gallons per hour, or even more. Because conventional systems do not allow for such lost water, the system may experience oversaturation or overrun of capacity after a certain volume of water. That is, the system continues to operate after the resin bed is unable to perform additional ion exchange, resulting in untreated water being output from the water treatment system.
U.S. Pat. No. 4,104,165 (Braswell), assigned to the assignee of the present invention, discloses a water softening system which may be regenerated on a timed basis. Braswell discloses a valve head assembly mounted to a treatment tank and having a poppet type plunger valve disposed therein. The plunger valve includes a venturi section which creates a vacuum within the valve head assembly and treatment tank to draw saturated brine solution through the treatment tank and into the valve head. A solenoid valve is disposed downstream of the plunger valve and is actuated to allow fluid flow through the plunger valve. All fluid which flows through the plunger valve also flows through the solenoid valve. A problem with such solenoid valves is that they typically have a relatively low flow rate, e.g., 5 gallons/minute maximum, which accordingly limits the regeneration time of the water treatment tank. Moreover, since all of the fluid flows through the solenoid valve when the solenoid valve is in an open position, debris and foreign matter within the fluid may lodge within the solenoid valve and cause improper functioning thereof.
It is also known in the art to use counter current and pulsating flow through a treatment tank to reduce the amount of time required to regenerate the resin bed and to more fully recharge the resin bed and to prevent channeling or fluidizing of the resin bed. For example, U.S. Pat. No. 5,108,616 (Kunz) discloses an ion exchange water treatment system using a pulsed, counter current flow of regenerant through the treatment tank. The duration of the pulsations and the time period between pulsations is such that the ion exchange granules making up the resin bed within the treatment tank are not substantially mixed during the regenerating process.
An advantage of solenoid valves is that they may be quickly opened and closed to thereby decrease the amount of time required to regenerate a particular treatment tank.
What is needed in the art is a water treatment system which induces a flow of regenerant through the treatment tank and into the valve head assembly very quickly, using less water and time in comparison with conventional units.
A further need is a system which utilizes diaphragm valves to quickly direct water in a particular direction within the valve head, while eliminating problems of debris buildup within and low flow rate through such a diaphragm valve.
An additional need is a water treatment system which allows various time periods for certain segments of the regeneration process to be quickly and easily altered depending upon water conditions, water usage, high or low pressure, etc.
A still further need is a water treatment system which allows for lost or unaccounted for water that has gone through the system and thereby eliminates overlap conditions associated therewith and rebuilds the bed if an overlap condition occurs.
An additional need is a water treatment system which monitors exact water usage of one or more tanks within a water treatment system and regenerates each particular tank according to the exact amount of water used by that tank.
A further additional need is a water treatment system which utilizes a vacuum pressure within the valve head to create a relatively strong suction pressure within the treatment tank and thereby removes substantially all the gases therein, i.e., degassifies the interior of the treatment tank and draws the regenerate in an undiluted state.